Instrument for dividing and multiplying angles



July, 1924.

J. F. VALKENBURGH INSTRUMENT FOR DIVIDING .MULTIPLYNG ANGLES FiledJax-n.18 1921 Patented July 8, 1924e UNITED STATES JOHANNES FREDERIKVALKENBURGH,YOF THE BAGUE, NETlllEiRLl'JANDS.V

INSTRUMENT FOR DIVIDING AND MULTIILYING ANGLES.

Appiication ined January a, 1921. serial No'. 435,848.

To all whom t may concern:

Be it known thatI, JOHANNES FREDERIK VALKENBURGH, a subject of theNetherlands, residing at The Hague, Netherlands, have invented certainnew -and useful Improve- 'ments in Instruments for Dividing andMultiplyiiig Angles, of which the following is a specification. i 1

For dividing .and multiplying-angles, setting off or developing straightlines and arcs upon straight lines or arcs etc., it has been suggestedto employ an instrument comprising in combination two indicatorsrotatably mounted on a common axis and each having its free endconnected with a cord or string, a ring secured to said axis and havingtwo grooves of equal diameter arranged axially side by side to serve asguide ways for the strings, and a leverV which is coupled with thestrings and adapted to move in a predetermined path in such a manner asto ensure a fixed but adjustable ratio between the distances throughwhich the fastening points of the strings on the said lever are moved,the arrange- -ment being so that the strings during this movementconform themselves to the paths of said points.

Starting from the underlying principle of the above describedconstruction the present invention has for its object a much simplerapparatus for carrying out the required planimetric manipulations. Withthis object in view I make use of the property that in a circle anglesat the circumference and also angles at the centre on equal arcs are allof equal size; in view of this property an instrument according to mypresent invention comprises an indicator which is rotatable about afixed axis and connected with a rectilinearly guided member in such amanner that a displacement of said member along its guide way produces aproportionate angular displacement of the indicator, and/or vice versa.special embodiment of my invention, the indicator is movable along acircular track which has its centre in the indicator axis, and connectedwith the rectilinearly guided member by a string which is guided alongsaid track. In another embodiment the indicator is provided with a gearwheel or In a` atoothed segmeiithaving'its centre in the said axisofrotation and cooperating with al rack on the rectilinearly guidedmember.

v Fig. 3 isvas'ection oii line 3-3 of Fig-2.V

Fig. lof the annexed drawing shows a View, partly in section, of aninstrument according to my invention. This instrument comprises a flatsemicircular ring l integral with a ruler 2.` AIn the centre of ring lis an axis 3 having a sharp point at its lower end and rotatable aboutthis axis is an indicator 4 adapted when rotating to slide over saidring. The straight edge 4a of the indicator is radial relative to theaxis of rotation. The ruler 2 is provided with a straight groove 5serving as a runway for a block 6 connected with a pointer 7 whichprojects from the ruler. The indicator 4 is connected with the block 6through a cord or string 8 lying in a groove 9 cut in the ring 'l andhaving its centre in the axis 3.

When I desire to employ the described instrument for dividing an anglewb into say six equal parts, I draw on Va sheet of paper a circle lhaving its centre in c and 'having any suitable radius, whereupon Ipress the sharp point of the Vaxis 3 into the paper yin a point e of thecircumference of the circle d. Then I first turn the edge 4a of theindicator 4 exactly along the line ealand subsequently move the block 6until the string 8 is stretched. Upon a straight line run in parallelrelation with the groove 5 and tangential to the free end of the pointer7 I now mark the point f indicated by the said pointer and I then movethe indicator 4: in a clock-wise direction until its edge ta is exactlyValong the line eb. I now mark upon said straight line the point gindicated by the pointer 7 whereupon I divide the distance fg into sixequal parts in a manner well-known to those skilled in the art. When Inow move the block 6 tothe right until the pointer 7 has reached thefirst division point on line gf and run along the edge 4a a line whichintersects the circumference c l in h, the angle beh is equal to theQue-Sixth part 0f the angle deb, and the angle heb is the onesixth partot the angle (wb. A proof for this thesis may be considered as beingsuperiiuous.

Neither is it necessary to furnish any il further explanation as to themanner in thereof.

second which to multiply a given angle and per- Jform othermanipulations by means of the described instrument.

When it is desired to avoid the use of a string, the block 6 may beconnected with a rack arranged in parallel relation with the groove andco-operating with a gear wheel or toothed segment on the lindicator 4with its centre in the axis of rotation Also in this case therectilinear displacements of the pointer 7 are at all timesproportionate to the angular displacements of the indicator 4.

Figure 2 of the drawing illustrates this embodiment of the invention. Inthis figure, 9 is a toothed segment integral with the indicator 4 andhaving its centre in e; said toothed segment 9 meshes with a rack 10slidably mounted in the instrument and carrying the pointer 7. A pinionl1 in mesh with the rack 10 serves for imparting to the latter therequired motion in the one or the other direction. The pinion 11 can beturned by means of a knob 12.

What I claim is: f

l. An instrumentV of the class described, an element forming an axis andhaving a piercing point at one end, an indicator angularly displaceableabout such axis, a member, means for rectilinearly guiding said member,and means whereby movement of said member compels a proportionateangular displacement of the indicator. Y

2. In an instrument of the classdescribed, an indicator rotatable abouta fixed axis, a member, means for rectilinearly guiding said member, agear rack on said member,

gear teeth on the indicator concentric with j' the axis thereof andadapted to engage the gear rack, and manually7 operable means engagingsaid rack to operate said member.

In testimony whereof I aix my signature.

JOHANNES vFREDERIKY VALKENBURGH.

